Method of forming tapered wheels



Oct. 3, 1944. R. c. INGERSOLL METHOD OF FORMING TAPERED WHEELS Filed Nov. 3, 1941 1;,- /Pa y C Ingeraoll 3 Patented Oct. 3, 1944 S PATENT OFFICE METHOD OF FORMING 'TAPERED WHEELS Roy C. Ingersoll, Winnetka, 111., assignor to Borg- Warner Corporation, Chicago, 111., a corporation of Illinois Application November 3, 1941, Serial No. 417,600

4 Claims.

This invention relates to a method of forming tapered wheels.

The principal object of this invention is to provide a method of forming tapered wheels from substantially rectangular blanks in a manner which will result in a minimum of waste.

Another object of this invention is to provide a method Of forming tapered wheels from sheet material in such a manner that a refined circular grain structure will be produced such that the resulting wheel will be strong and may be more readily gripped in a die when the wheel is given its final form.

Another object of this invention is to provide a method of forming tapered wheels having a central fiat section and a tapered outer section, the central'regionbeing of constant thickness.

Another object of this invention is to provide a method of forming a wheel body having a tapered outer section and a flat central section of constant thickness, the tapered region being formed by rolling and spinning the metal radially outwardly and the flat central section being formed by rolling and spinning the metal radially inwardly.

These and other objects of this invention will become apparent from the following specification when taken together with the drawing in which:

Fig. 1 is a perspective of a blank from which the wheel is to be formed;

Figs. 2, 3 and 4 show the blank in intermediate stages during the formation of the wheel;

Fig. 5 shows the blank being heated;

Fig. 6 shows the heated blank being expanded to an intermediate cone form;

Fig. 7 shows the blank expanded to its final form preparatory to rolling;

Fig. 8 shows the blank being taper rolled; and

Fig. 9 shows the blank being rolled over its center section.

Referring now to the drawing for a detailed description of the invention, the initial step comprises cutting off a, length 20 of substantially rectangular form from sheet stock 2|. The material selected may be any analysis suitable for the production of wheels, The proportions of the blank 20 are so chosen that the width of the blank is considerably smaller than the radius of the finished wheel and the length of the blank is considerably less than the circumference of the finished wheel. A ratio of width to length of 1 :6 has been found to be satisfactory although this Ifltio may vary slightly in either direction. In one example abar 35 inches long, 6 inches wide and e of an inch thick was found to be suitably proportioned, The ratio of width to length is important since if not properly chosen, there will not be a proper distribution of metal for the subsequent rolling and spinningoperations.

In the nextoperation, blank 20 is curled into a cylinder as shown in Fig. 2 with the ends 22 of the blank abutting one another. This operation may be performed by any well known curling apparatus. v

The curled blank is then welded along the abutting edges as shown in Fig. 3 at 23 to form a substantially endless cylindrical section. It is important that the weld be as free from defects as possible so that this part of the blank will be substantially as strong as the stock from which the blank is formed. a

After the abutting ends have been welded, the excess material at the weld is stripped off as shown in Fig. 4 to provide smooth interior and exterior surfaces for the blank.

In the next operation, a number of welded blanks is placed in a heating furnace and heated thoroughly to a forging temperature. A temperature Of 1800 Fahrenheit has been found to be satisfactory, The heated blank is then formed preliminarily into a cone by means of pressing dies 24 and 24a as shown in Fig. 6. .In this operation one end of the cylinder is expanded while the other end is contracted in the formation of the cone. To minimize stresses in the blank and particularly at the weld, the preliminary coning operation is designed to produce a 45 cone angle which is steeper than the desired angle. The coning operation results in a slight taper in the blank which decreases to some extent the amount of work required to be done by the subsequent rolling and spinning operations. At this stage, start-' ing with a35 x 6" x blank, the center opening of the cone will be between 8 and 9 inches in diameter.

The final coning operation is shown in Fig. 7 and in this operation the cone is still further expanded by means of dies 25, 26 to approximately 30. Simultaneously, a fiat central section 21 is formed which provides an inside corner 28 adapted to facilitate centering the blank on the rotating platen of the spinning machine. The flat central section 2! may, if desired, be formed by a separate operation.

The blank may be reheated to approximately 180 0 Fahrenheit and is then ready for the rolling operations. It is contemplated that the entire surface will be subjected to a combined rolling and spinning operation; This not only produces the proper variations in thickness of the blank,

. but also works and refines the metal to produce a superior grain structure and most important of all, it refines and works the material at the weld to such an extent that the weld is indistinguishable from the remainder of the blank.

'The spinning platen for affording a support for the blank during the spinning operation is shown at 29 in Fig. 8. In this figure the blank is shown being spun and rolled in order to expand its diameter and to taper its section, Two rolls 30 and 3! are used which are made to contact the blank initially substantially over the corner region 28 of the blank and are then moved simultaneously outwardly across the surface of the blank by any suitable means until the desired diameter and tapered section are achieved. The rolls may be identical in form and are preferably moved simultaneously on opposite sides of the blank in order to equalize as much as possible the forces acting upon the blank. They are pref erably moved along a line parallel to a radius so as to develop a force component which assists in moving the rolls outward.

In the next operation, the blank is transferred from platen 29 to another platen 32 and a roll 33 is then moved radially inward from corner region 24 to reduce the size of the opening at the center of the blank and also to reduce the thickness of the metal to a uniform cross section. The finished blank, using again an initial blank of 35" x 6 x fe, willhave an outside diameter of about 23 inches and a central opening of W about 5 inches.

After the blank has been rolled as shown in Fig. 9, it may then be formed into the final shape desired for the wheel by the usual press operations.

It will be observed that no material has been removed from the blank from the time it was in rectangular form to the time it is in the form shown in Fig. 9. It will also be observed that during the rollin and spinning operation the metal of the blank, includin the weld, was refined to a denser and stronger structure. Actual tests and photomicrographs have shown that the portion of the blank which has been welded was indistinguishable from the remainder of the blank. The circular rolling also produces a smooth outer periphery in the blank which may be efiiciently gripped in a drawing die when the blank is given its final form.

The division of the rolling and spinning operation into two steps such that in one step the metal is rolledand spun radially outwardly and in the other it is spun radially inwardly, makes 7 it possible to use a narrower blank and therefore The coning operations may be performed while the blank is cold, the only difference over the hot forming steps being in the number of operations required. Thus it might require five separate coning operations for a cold blank against the two hot forming operations shown. Similarly only one coning operation may be used when and some other centering device used. For example, the blank might be left in the form of a cone and a central lug the size of the opening in the cone may be used to center it in the subsequent spinning and rolling operation.

Although the invention has been described with reference to a tapered wheel body it is intended that the scope of'the invention should not be limited to a wheel body having a tapered cross-section. The method canbe applied to a blank wherein variations in cross-section other than a taper may be desired. The final shape of the blank just prior to the rolling may be chosen to suit particular requirements and need not be limited to a conical form. If necessary additional flattening operations may be performed upon the blank to produce a flat disc as the starting blank for the rolling operation.

The rolling of the weld constitutes a very important feature of my invention since in rolling out the wheel the same refining process occurs as is present'in rolling ingots and this process creates a homogenous structure throughout the blank which results in much greater strength and life in the wheel or other article produced from the blank.

Another feature of my invention which I consider to be important resides in the reduction of the central opening in the blank by rolling the metal inward from some intermediate diameter. With the aid of the rolling-in step it is possible to produce any predetermined size opening at the center of the blank merely by properly choosing the intermediate diameter from which the rolling is started. By using the proper starting diameter just sufiicient metal is provided to pro duce the center hole desired without any waste except for trimming the opening to render it perfectly smooth and true.

It is understood that the foregoing description is merely illustrative of a preferred embodiment of this invention and that the scope of the in-.- vention is not to be limited thereto but is to be determined by the appended claims.

I claim: a

l. The method of forming tapered wheels which comprises forming a rectangular blank, curling the blank into a cylinder, welding the abutting edges of the blank, expanding one end of the cylinder and contracting its opposite end to form a relatively steep cone by pressing the cylinder between appropriately shaped dies, thereafter expanding said one end further to form a flatter cone and forming a flat central section by pressing the cone between other appropriately shaped dies, spinning the conical section by simultaneously rotating the cone about its central axis and moving a spinning tool forcibly applied on the conical section outwardly toward the outer edge of the section whereby to work the metal in the conical section outwardly, and operating on the fiat section to reduce its thickness and to decrease the site of the central opening.

2. The method of forming tapered wheels which comprises forming a rectangular blank, curling the blank into a cylinder.- welding the abutting edges of the blank, expanding one end of the cylinder and contracting its opposite end to form the blank is heated instead of the two shown.

The shoulder shown in Fig. '7 may be omitted a cone and forming a flat central section on the smaller end of the cone by pressing the walls of the cone between appropriately shaped dies, and moving a spinning" and rolling tool forcibly applied to the conical section outwardly to expand and thin this section.

3. The method of forming tapered wheels which comprises forming a rectangular blank, curling the blank into a cylinder, welding the abutting edges of the blank, expanding one end of the cylinder and contracting its opposite end to form a cone and forming a fiat central section on the smaller end of the cone by pressing the walls of the cone between appropriately shaped dies, spinning and rolling the conical section to expand and thin this section, and spinning and rolling the flat central section to reduce the thickness of this section and decrease the size of the central opening.

4. The method of forming tapered wheels which comprises forming a rectangular blank, curling the blank into a cylinder, welding the abutting edges of the blank, expanding one end of the cylinder and contracting its opposite end to form a relatively steep cone by pressing the cylinder between appropriately shaped dies, thereafter expanding said one end further to form a flatter cone and forming a flat central section by press ing the cone between other appropriately shaped dies, spinning and rolling the conical section to expand and thin this section, and spinning and rolling the flat central section to reduce the thickness of this section and decrease the size of the central opening.

ROY C. INGERSOIL 

